Material having improved magnetic property



A DeC' 13, 1951 H. w. LEvERENz ErAL 2,579,267

MV1 z 3'4 5 a 7 MATERIAL HAVING IMPROVED MAGNETIC PROPERTY Filed Dec 51, 1947 yvvv v vvv 4 bare J He yz BY atented Dec. 1:8, 195i f f t .Y 2,579,267

MATERIAL HAVING IMPRovED MAGNETIC PRorERfrrY A Humboldt W. Leverenz and Imre J. HegyL'Princeton, N. J., assignors' to Radio Corporation of America, a corporation of Delaware Application December 31, 19.47, Serial No. 795,046

This invention relates to materials having improved magnetic properties. These materials may have unusually high values of magnetic permeability, or they may have desirably low loss values (high Q factors) at radio frequencies, or a usefully high product of these two values. They may also have desirable properties of magnetostriction and good stability at operating temperatures. They may also have an improved modulus of elasticity and good resistivity.

Wherever Q values are discussed or stated throughout this specification, there is meant a numerical value foundby dividing the radio frequency reactance by the resistance of a circuit in which the materials of the present invention are introduced as induction coil core bodies. l

More particularly, the present invention relates to materials known as ferrites, made by the general method described in co-pending application of H. W. Leverenz and R. L. Harvey entitled Improvement in Magnetic Materials, Serial No. 776,292, filed September 26, 1947, now Patent No. 2,565,861.

The present improvement is especially related to the use of beryllium oxide, BeO, either substituted for part of the oxides previously disclosed,

One object of the present invention is to prov-y vide compositions having improved magnetici properties.

Another object of the invention is to provide materials having controllable and unusually'high values. of magnetic permeability.

Another object of the invention is to provide materials having low loss values (high Q factors).

Another object of the invention is to provide materials having improved magnetic properties and alsoA high Curie temperatures. n 1

. Another object of the invention is to provide materials having a desirably wide range of magnetostriction.

Another object of the invention is to provide materials having improved magnetic properties along with a desirable modulus of elasticity.

' Another object is to provide improved compo-,- sitions of magnetically permeable ferrites which include beryllium oxide as an essential ingredient.

Still another object is to provide materials having desirable values of resistivity.

These and other objects will be more readily apparent and the invention will be better understood with reference to the following specication, including the drawing, of which the single provement in the product Q obtained tion of BeO in a Ni-vZnA `ferrite.

9 Claims. (Cl. 252---62.5)I

Although thecompositions, which are a part of the present invention, are different from those described in the previously mentioned co-pending application, Serial No. 776,292, the general method'of preparation is the same as illustrated therein. Briefly, this method includes the intimate mixing of ferric oxied and the various other oxides involved. each in a ne state of subdivision, heating, preferably, a compressed body made of these oxides within a range of temperatures 'of about 900 C. to about 1500 C. for about 1 minute to about 5 hours in an oxidizing atmosphere, and then cooling. Longer heating times are required for larger bodies. Optimum conditions of time and temperature of heating will vary with each specific composition possible within the systems of compositions which are a part of the present invention and, with any specific composition, the optimum heating time decreases as the temperature of heating increases. In general, however, some improvement in results is obtained by selecting widely varying times and temperatures within the ranges specied, even though these improvements will not be the maxiof the order of 1200 C. has proved satisfactory, if not always best, with all of the compositions.

mum obtainable when ahmore careful choice is made. Good results can be expected with almost any of the compositions, if a heating time of V about 1 hour is used, and a heating temperature The reaction product which is fromed in all instances is a composite, homogeneous, crystalline is not known and cannot easily be determined.

The oxidizing atmosphere in which the heat- 3 ing of the reaction mixture takes place may be helium or nitrogen, but the improvement is not as great as when an oxidizing atmosphere is used. In contrast to the use of either an oxidizing or a neutral atmosphere, the presence of a reducing it possible to start wvvith a mixture ofkmateatmosphere, such as supplied by carnbon monoxide or hydrogen, in the reaction chamber, is distinctly detrimental, if 'materials having high permeability are desired. Therefore, it may bev said that the heating should take place in a nonreducing atmosphere. preferably at atmospheric or higher pressures.

Instead of starting with the oxides themselves,

containing FezOs, the iron may be in the forni of ferrous oxide or magnetite, providing thaty heating takes place in an oxidizing atmosphere, and as the hydroxide, carbonate, etc., if either an oxidizing or a neutral atmosphere ispresent.V

The other ingredients may also be present forms such as hydroxides, acetates or carbonates or either lower or higher oxide forms than-'- are present in the nal product, since thesewill revert to the desired oxide form when heated strongly in. the preferred oxidizing atmosphere arid, insme eases, evenin a'neutral'atmosphere. Certain o'f the present compositions' also utilize oxideso'f manganese. This is preferably' present as MnOz the initial mixture but changes to MnO irrtlie reatio'prdct. This` change oo,- curs even though an" oxidizing atmosphere be used, providing the'oiidi'zatiori properties of the atmosphere are not strong enough to prevent the reduction of thth'ighe valent oxideto'the lower divalent forni. Likewise, other oxidesv of man gfanes dan' be used'in the starting mixture since these will'revert t when heated in the oxidizing atmospherei Similarly, it is possible to use oxide of copper Vdi" nickel since. therev also will Change to the desired foriii whenA heated underV the oxidizing` conditions preferred;

Because of tlebrttlee'ssf the reation prod'- uct's; oinprssed bodies ofv the reactants may be fortified at pressures of, say, 20,000V pounds per square inch and these compressed bodies are treated at' elvatedteriiperatures'in order to impart the desired properties' of increased permeability, low loss, etl, desired iii. the end product. These compressedbodiesmay also be' formed" by extrusion molding processes at mush liier"pres#A sures. The fact that shaped bodies of the compressed material can be formed without' thepresence' of a permanent binderadds rinih to their improi/'iet over" materials. previously` known, such as pwderedin) reires'jthe'u'se. of a permanent binder, since the binder introduces almultitude of g'flso considerable size between the particles, arid-` the gaps, themselves arev re,- sponsible for fuch o`f` the lower permeability hitherto present"` in materials `of. this nature. When the material is iade in the forrn'of com-r pressed. bodiesthe. pressure of forming may vary widely: APressures of; 2,() pounds per squarel inch havebe'e found to produce the. saine improved results as those ten times as greatand'extrusion molding techniques. have been sedwith excellent results. For example,l the ingredientV oxides may be preLheated, .mixed with a',- temporary binder and extrusion molded y and heat treated. In generaLit may be said that'the pressure. of forinshould be siicient to forma closely coherent. bodyV and' the` pressures used should simply be those. necessary to obtain this result.V

After the heat treatment has been.l accomplished as described', the reaction product'is pref'- erably, although not necessarily, cooled very rapidly as. by subjecting .it tov a blast of air or quenching in water. Rapid cooling'generally increases the permeability and low loss. qualitiesV above those values obtained when slow coolingis used.

The reaction mixture may be compressed into any desired'sh'ape before heating takes place in the reaction chamber. The danger of warping of the compressed bodies, when heated, may be lessened by mixing a small percentage of a lubricant with powdered oxidesbefore compression. The preferred lubricants' are those which are completely burned off during the heat treatment process. Suitable examples are stearic acid and microcrystallinewaxes, such as Carbowax.

Other improvements in molding technique are described in the previously mentioned co-pending application,I such"l as'releasing pressure uniformly from the Vm'old. piston after compressing the oxide mixture i'nt'o the desired shape.

As previously stated, the present invention relates more specifically to the use of beryllium oxide in ferrite bodies, prepared as described. In a wide rangeof compositions, it has been found that the' additiorjofiberylliumoxide produces desirablei improvements not obtainable when mix/L" tures ofl oxides; not includingberyl-liumoxide; are used; 5

One of" the new` systems, according tothe pres'- ent invention, is'afquaternary system comprising BeO; MnG, Zn-O- and FezOs. In Table I below are given examples* of various compositions or these four ingredientsexpressed in mole parts.y First, there is givenn aJ/ composition with the beryllium-oxide ornitftedfand thisi-svfollowed by comporsitionsjir-rl which variousfsrria-lllpropor-tions o within the rangeo'foperati-gf temperatures, the

,magnetio properties Lm'ay* vary quite widely when the material is in use. The values in Table I were: obtainedby crystal-lizin'gi the materials a 1200 ina'n oxygen' atmosphere.

1n 'die above system, is has been foimd'uiat the 00 physical natureie: g., density, partiole'size, degree than` 0.1' iieronl.. Thef dgje cifpurity of the M1102 and tlie'ifrigrdihts is also. an important factor., hish puritybeig" desirable. Duringv the crystallization proess, brought, about by theV heat treatment, the M`O2 deeojiriposesl to. afford MnO.

BO `w"as alsoV substituted forl part of the M1102 prepairingV Vmaterials'. falling Within the BefO ZnO :MnOiFez'Oa systrriz with results shown by the examples listed Table-,12A.- It Will be'y seen.

u that here, also, the' iisef' BeO resulted in corni the iran-ganese.Y dioxide inais'rogaerpositionshaving improved magnetic properties.' Crystallization Wascarried out at 1200 fC.' in oxygen Y f 1 v 1 Tobie IA Keepingv the ZnO and M1102 content constant. BeO Was also substituted for part of the Fe20a in preparing materials within the system Y Beo zno:Mno4.Fe2o3 with' results illustrated in Table IB. Crystalliza- *Another modification in the method of preparing crystalline materials within the system was carried out by adding BeO with molecular proportions of all of the other ingredients re'- maining constant. Crystallization was carried out at `1200 C. in oxygen. Data are shown in TableIC.

Table IC BeO Z110 MnOa FezOs #ou Q #Q In Table II below, values are given for a crysjA talline system comprising VBeO ZnO NO :Fe203 The values in this table were obtained by crystal-A y lization of the materials at 1400" C. in an oxygen atmosphere.

Table II Curie BeO Z110 N10 FeaOa non. Q #Q Temp 0 0. 35 0. 15 0. 5 15. 2 39 593 80 0. 02 0. 33 0. 15 v 0. 5 Y 15.2 72 1090 180 0. 125 O. 225 0. 15 Y 0. 5 14. 4 82 Y 1180 276 0. 2 0. 15 15 0. 5 8. 4 76 Y 638 Y.. 0. 3 O. 05 0. 15 Y 0. 5 Y 3. 3 102 337 0 o. 25 0. 25 0.5 12. 5 54 '675 0. 05 0. 2 0. 25 0.75 12. 2 85v l 1037 0. 125 0. 125 0. 25 0. 5 9. 2 95 874 0j 0. 325 0. 175 0.75 14.9 59 879 0'. 02 O. 305 Y 0. 175 v 0.5V 14. 3 77 A 5 1101 0. 1 0. 225 0. 175 0. 5 12. 6 86 Y Y 1084 0 0. 35 0. 1 0.755 13. 3 30 Y 399 0. 05 0. 3 0. 1 0. 55 13. 2 63 832 A 0 0. 4 O. 05 0. 55 2. 6 11 29 0. 05 0. 35 0. 05 l 0. 55 13. 2 31 409 0 0. 35 0. 35 0. 3 4. 0 Y 38 152 Y 0; 1 0. 25 0. 35 0. 3 4. 1 48 197 0 0. 6 0. 1 0. 3 7. 3 18 131 l 0. 1 0. 5 0. 1 0. 3 6. 0 30 180 0 0. 15 0. 15 0. 7 a 7. 3 111 810 0. 025 0. 125 0. 15 v 0. 7 Y 6. 5 77 A 501 0 0. 1 0. 1 0. 8 4. 4 83 365 0.025 0.075 0.1 0.8 3.5 75` Y 202 In the above tablepitwill be noted that data are given for compositions in which various percentages of ferrie oxide are used and also" in whichthe nickel oxide and zinc oxide are varied widely.

In Table III, values are given for a system comprising BeOzZnOzMgOzFezOa. These values were obtained by crystallization at 130()u C". in an oxygen atmosphere.

Table III Table IV contains values obtained for asystem comprising BeO:ZnO:CuO:Fe2O2. The values were measured for materials crystallized at 1200 C. in an oxygen atmosphere.

Table IV Boo Z Guo F5203 ,.m, Q Q .Ie

c. 0 0. 8 o. 2 0. 5 14. 2 20 284 40 0.02 0.28 0.2 0.5 14.2 30 42s 0.07 0.23 0.2 0.5 15.2 59 897 130A 0.1 0.2 0.2 0.5 14.4 73 1,051 0. 15 0.15 0.2 0.5 12.5 72 900 0 0. 35 0. 15 0. 5 1. 04 53 55 0.05 0.3 I 0.15 0.5 4.0 20 80 0 0. 4 0.1 0. 5 1. 2 29 35 0.02 0.38 0.1 0.5 1.2 35 42 0. 05 0. 85 0.1 0. 5 1. 02 57 58 0 0.35 0.2 0.45 1.05 50 53 l 0-05 0.3 y 0.2- 0. 45 1.8 V20 80 0 0. 25 0. 2 0. 55 15. 7 42 550 0. 05 0. 2 0. 2 o. 55 14. 9 80 894 Table V contains values for a few examples of n' VYcompsitions Within the system BeO CdO CuO: Fe203 Crystallization was at 1200* C. in an oxygen atmosphere.

Table V BeO CdO CuO FezOa um Q MQ 0. a0 0. 20 o. 50 13. 0 20 272 o. 02 0. 28 0. 20 0. 50 14. 0 25 350 0. 05 0. 25 0. 20 0. 50 14. 2 85 497 0. 10 0. 15 0. 20 0. 50 12. o 71 852 BeO Z110 MgO Fe201 non. Q #Q ragga Y D Cl 0 I 0. 25 0. 25 0. 5 15. 1 44 664 115 0. 02 0. 25 O. 25 0. 5 13. 2 57 752 356 0. 1 0. 15 0. 25 0. 5 10. 3 65 670 0. 0. 125 0. 25 5 9. 2 60 552 k0. 2 0. 05 0. 25 0. 5 4. 4 75 330 0 0. 35 0. 15 0. 5 1. 2 27 32 0.05 0. 3 0. 15 O. 5 8. 3 30 249 0 0. 3 0. 3 0. 4 1U. 0 23 230 O. 02 0. 28 0. 3 0. 4 11. 8 18 212 0. 05 0. 25 0. 3 0. 4 9. 5 37 352 0 0; 35 0. 35 0. 3 5. 0 8 40 0. 05 0. 3 0. 35 0. 3 6. 0 22 132 0 2 O. 2 0. 6 9. 2 70 644 0. 02 0. 18 0. 2 0. 6 9. 7 65 631 0. 05 0. 15 O. 2 0. 6 8. 2 75 615 0 0. 225 225 0. 55 12. 1 65 786. 5 .1. 0. 05 0. 175 0. 225 0. 55 10. 5 75 788 0 0. 3 0. O5 0. 65 10. 9 50 545 0. 02 0. 28 05 0. 65 8. 6 95 817 7 Table VI corporation of BeOtoA b euseiul., Perhapsl the.

greatest improvements.. onincOrpora-ting Bco.: occur in those compositions having Curie tern- -v Be@ Odo M302 F6201 Q 1 Q peratures near roomtemperature. As shown in Y 1 5- the above tables, the incorporation of BeO benegj gg cially raises the Curie temperature, as well as 0.10 0.15 0.2 5 0. 50 10.5r 05 080 the product ILQ. This useful effect of BeO extends the range of useful compositions which are usable .at a given temperature.` ...15555 5555555.55555 raarste w improvement in LQ basic ternary System about by the inclusion of BeO 1n the ferrite Sys- T Y tems is illustrated graphically in the figure. The

able VII shows the effects of adding BeO to gure shows the extent of improvement that it the system MnO:ZnO:CdO:Fe2O3 to form a penis Ossrible to. Obtain .by addin an optimum tanar system including BeO. The Q value .of p .g d

y amount of BeO to ferrites of the system the mammals 1S false@ conslderably Crystamza NiOzZnOtFezOs'. The examples given are those tion'was at 1209 C m an Oxygen atmosphere in which an amount of BeO is. added such that Table VII the maximum increase in value of ,4Q is obtained. It willbe noted that a composition made. up of B00 Z110 odo i M1105 F0203 .ff. ,LQ 204 a mixture of 50.111010 percent Fe2O5,.15 molexper.. cent NiO, and 35 mole percent ZnO can have its 0 0,125 0.125 0.25 0.5 1.5 4 29 447 4Q product increased by about 530 units When 0-05 0-10 010 I 125 05 14-3 72 1030 an optimum amount of BeO is included in the composition ,before crystallization. It will be not- In all Aof the above systems, the beryllium oxide ed further that, when the compositions contain was added to the mixture before the mixture was about mole percent Fe2O1, the maximum poscompressed and crystallization carried. out. In sible improvementA is very small, While,` for comgeneral, it has been found that the addition of positions containing above about 70 mole percent about 0.2 to about 30 mole percent of co-crystal- Fe203, `the addition of BeO may lower the 1Q lized BeOimproves the product MQ (gure of product; no matter what amount is added. The merit) of the ferrite-solidand somewhat higher OQ gure also illustrates the relative improvement values. (e. g., up to about mole-percent BeO). possible to bring about by; adding BeO since the may be used to obtain` improved Q Va1ues,.al increase in value sometimes amounts to several though the product ,1Q may not be improved hundred percent. when the highest percentages of BeO are used. Although the greatest. improvement in mag.- When a composition of the three ingredients, a netic. properties hasbeenfound when BeO is inwithout beryllium oxide, is selected, which is eluded in a Quaternary system type ferrite, it has near the optimum for maximum n, it has been also been found that compositions having use- Iound that the optimum proportion of co-crystalfully improved magnetic properties can be oblized BeO is about 3 to about 15 mole percent. tained by utilizing varying percentages of BeO in When the ternary-system composition is high in 40 a, ternary system. Data illustrating examples of iron oxide, the addition of BeO may lower the various ternary system ferrites, including BeO, product 10Q; hence, the improved materials are given in Table VIII. It will be noted that should preferably comprise no more than about some significant improvement is obtained in` almole-percent of iron oxide. Furthermore, most all instances by the addition of BeO alcompositions which have less than about 30 mole- 45 though the percentageof improvement is not as percent of Fe2Os have poor characteristics which great, in general, as when the BeO is added or are generally not improved suiciently by the nsubstitutedv to form a q'uaternary'system.

Table VIII F410, M1104 zno'.. MgoV i N10 Guo. B40 ,1.11, Q o

0.40 0.00 5.5 45 22s 0.40 0.45 0 15 5.5 es 410 0.501.V 0.50 0.7 55 350 y.0.50. 0.40 0.10 4.2 75 315l Y 0.50 0.40v 5.5 00 315 0.00 0.30 0.10 2s 100 200 0.45 0.55 7.4 Y 25 105 0.145 0.45 0.1.0 0.4 4o. :050l

Table VIH-continued F8203 M1102 Z110r MgO N10 C110 B00 um. Q #Q All of the above values were obtained by add- 21/2 inches. The tube was wound with a soleing BeO to the various oxide mixtures and then Vforming compressed bodies and heating in an oxi- .dizing atmosphere.

The heating temperature was 1200" C. except that those compositions containing `N10-were heated at 1400 C., those containing MgO were heated at 1300 C. and those .containing ZnO were heated at 1400" C..

From the data given in the above table, it can ,be seen that, in some cases, the addition of BeO .to a binary system ferrite does not improve the magnetic properties as much as by adding it to a ternary system and'in a few cases a slight de- .crease is noted. However, the proper standard of comparison is a similar body made of powdered iron which was formerly the best material known for high magnetic permeability. In all cases, the

lmaterials composed of the `ternary system ferrites, including BeO, evidenced improved properkties when compared to similar bodies made of powdered iron compressed with a binder.l Moreover, for special uses, ternary system products,

including BeO., have been found best since the Q values are usually high and the ,LQ product is also sufficiently high to be useful.

Of all of the above systems which form a part of the present invention, a quaternary system is preferred in which BeO and ZnO are both present. These compositions have proved best as to Addition of many other oxides has been tried. The addition of CaO, BaO, T102, and ZrO2 usually lowers both effective permeability, n, and Q1 Addition of any of T1102, $13203, A1202, SiO2, S110, B203 or Cr2O3 sometimes gives compositions having moderately improved ,uQ but the eiective permeability is usually undesirably lowered.

Although it it is not desired to be restricted to' the following theory, it is believed that the benecial effects of adding BeO (or MgO) to the ferrite compositions may be related to the higher @polarizing power of the Be++ (or l\/ig-++) ions and the higher melting points of the. BeO (or MgO). .Thenpolarizing power,.for example, is proportionalto q/r, where q is. the valence charge andr vthe ionic radius. Be++ exhibits' an outstandingly high ratio of q/r. Another interesting and important property of compressed bodies made up of compositions fallling within the present invention is that of magnetostriction. Magnetostriction is evidenced by the ability of a bodyto lengthen in one dimension and contract in another direction when subjwjected to a magnetic field. Measurements were made on compressed cores of the materialsinsertedwithin ahollow tube 11/2 inches `long and `having 1A; inch outside diameter. The cores were rectangular in cross section and had a length Qf noid of 990 turns of. No. 30copper wire. Measurements were taken using .two different field strengths, namely, y49.0. oersteds (M1) and 150.5 oersteds (M2) The former was obtained by applying abatterycurrentof 0.15 ampere at 1.5 volts and thelater eld was. obtained by applying .a battery. currentof0.46 :ampere at 6 volts tothe solenoid. Y

` Some of the ycore bodies 'exhibited only positive magnetostriction, as evidenced by increase in length, and others only; negative, while some exhibited positive at one eld strength and negative at another.'y .Inthefollowing table (Table IX) some examples of typical results are-given, the positive values, that is lengthening, being designated -P- and negative values, that is shortening, being designated -N-. All values are relative, abarof nickel of similar dimensions being taken as a standard and assigned the value 4N when subjected to a field of L19-oersteds. A system of levers-was used to magnify the amount of dimensional lchange and the amount of the change was measured byvobserving the movement of a knife edge connected to the lever system. The units expressed in the table are simply taken'vin-terms of the gradations of the scale of the observing scope.

' Table IX 40l 150.5 BeO Z M1105 FezOa oersteds oersteds 0.025 V0.225 0. 25 0.5 0.7N 13N 0. 075 0. 175 0. 25 0. 5 1. 71 1. 0N 0.125 0.125v 0.25 0.5 2.0P 0.4N

B50 rzno N10 F0204 M1 M2 0 0.35 0.15 0.5 0.5N 05N 0.02 0.53 -0. 15 0.5 13N 1.0N 0.125 0.225 0.15 0.5 18N 1.8N 0. 2 0.15 0.15 0. 5 1. 3P 0. 7P 0.3 0.05 0.15A .0.5 0.31 00P BeO Z110 MgO Fe201 M1 M2 0 v 0.25 0.25 y 0.5 0.5N 0 7N 0.02 0.23 0.25w 0.5 1.5? 0.1 0.15 0.25 0.5 0751 0er 0.2 -0.-05 y 0.25 0.5 10P 1.s1 0.1 0.2 0.2 0.5 0. 7N 05N 0.15 0.15 0.2 0.5 00N 1.0N 0. s 0 0` 2 0. 5 0. 25P 0.1?

From the figures in Table IX, it can be seen that, if a body having a certain magnetostriction is desired, it is simply necessary to select the proper composition and prepare a crystalline ferrite body in the manner described herein.

` The above examples contained in the several tables are not to be construed as limiting the invention to thefspeciii ycompositions listed therein. These have been chosen for purposes :arrasar 'f1-1 oi illustration only and have been selected from a larger mass of data. The approximate limits of practical operation have been pointed out.k

elsewhere above and it is these limits as well as those found in the appended claims whichit is desired to encompass within the present invention.

In general, the present invention constitutes the discovery that the addition of beryllium-oxide to crystalline ferrite materials containing atleast one other oxide of a certain group of -oxides results in the formation of materials having improved magnetic properties, especially if compared with the best previously 1known materials .formerly used for the same purposes, `such as Y.powdered iron. The group Yo1' other oxides yfrom more mav also be'used although, apparently, no

additional advantage'is gained by so doing.

The improvementin results obtained through use of the present Acompositions may be in any one or more of several categories; hence, whether or not a certain material constitutes an improved product compared with vprior art materials cannot be iudged by any onetest. Certain of the compositions exhibit exceptionally high` values of magnetic permeability, othersfhave exceptionally low loss factor (high Q), some have a desirably high product of 'these two values, others have desirable magnetostri'ctive properties and still others have lgreat stability-although their permeability or Q values-maynot 'be as high as any one of a number oi .other possible compositions. In some cases, a composition may have excep tionally high Curie temperature and thus be usefull for certain applications.

We claim as our invention:

1. A composition of matter comprising the reactionY product produced by heating together in a non-reducing atmosphere at `teiripi-n'atures oi 900 C. to 15'00" C. `for I1xninute to 5 hours an intimatel :mixture lof from "30 to '70 vmole percent FezOx, 0.2 to 50 mole percent BeO, and the re mainder comprising at least 20 mole jpercent one other oxidefrorn the class consisting of the oxides of manganese, zinc, magnesium, nickel, cadmium and copper.

2. A composition, according to claim 1, in which the amount of BeO Vis lfrom about 0.2 to about 30 molepercent.

3. A composition, according to claim l, in which the amount .of BeC-.is about 3 to. about 15 mole percent.. 4. A` composition, of matter comprising the reaction product produced by heating together in a non-reducing atmosphere at' temperatures of a non-reducingatmosphere at temperaturesof 900 C. to r1500i7 C. for 1 minute. to-5 lxoursz an I2 intimatemixturenot.abouto to about '70 mole percent FezOs, about 0.2 'to 50 mole percent BeO, and the remainderv comprising atleast 20 mole percent of two oxides of different Ymetals `from the class consisting of -oxides of manganese, zinc. magnesium, nickel, copper and cadmium.

6. A-composition-cf matter comprising there- 'action product produced by heating together in a non-reducing atmosphere. for 1 minute'to 5 rhoursfat temperatures of 900 YC. to 1500 C. an

intimate mixture of about 30 to about '70 Amole percent FezOa, about 0.2 to about 50 mole percent BeO, and the remainder comprising at least 20 mole percent of ZnO and 'atleas't'onefoxide from the class consisting Aof the oxides yof manganese,

l magnesium, nickel, copper Iand cadmium.

7. An article of manufacture characterized 'by having improved magnetic properties comprising a compressed body of material "of predetermined shape, said material-comprising a reaction product produoedby heatingtogether vin ka non-reducing, atmosphere ata temperature yof 900 C. to

1500'C.for l minute to 'hours an intimate'mix'- 'ture of 30 to 70* 'mole percent FezOi, '02 to -50 mole percent BeO and Yat least 20 mole percent vof an oxide from the class consisting 4of the voxides of manganese, Zincy magnesium, nickel, Copper and cadmium. y

8. An article of manufacture rcharacterized by having improved magnetic properties comprising a compressed body of materialof predetermined shape, said material comprisingv a reaction prodprisilflgpreparing an'intima'te mixture of `30 to A7.0

mole percent FezOs, 0.2 'to 50 :mole percent v'BeO .and at least 20 mole percentcf anY oxide from'the class consisting of Mn02, Z110, MgO, NiO, C and CdO,.compressing said mixture to form V1a. coherent molded body of vpredetermined shape. subjecting said. moldedl body 'to a temperature .of 900 C. to 150GD C.in..a non-reducingatmosphere for 1 minute to 5 hours to form .a Vcrystalline substanceY having `a deiinite chemical composition, and cooling said `crystalline substance.

HUMBOLDT W.Y LEVERENZ. IMRE J.. I-IEGYL REFERENCES CITED 'The following references are of record in the le o'ffthis patent:

UNITED STATES eA'inNTs Number Name Date 1,946,964 Cobb ---1--.. Feb.. 13, 1934 j' 1,976,230 Kato. Oct'..f9, 1934 l OTHER REFERENCES i Snoek: "Magnetic and Electrical Properties. of the Binaiy Systems MoEezOs, published in Physica, III, No. 6, June, 1936, pages. 481-482,.

Mellor: Comprehensive Treatise. on Inorganic and Theoretical Chemistry, voL 14r 1.934; Page 9,14.

. Kawai: .Journal of ther Society of Chemicallndustry, J apan,.vol.,37,.No..4, 1934, page. 17.4B. 

1. A COMPOSITION OF MATTER COMPRISING THE REACTION PRODUCT PRODUCED BY HEATING TOGETHER IN A NON-REDUCING ATMOSPHERE AT TEMPERATURE OF 900* C. TO 1500* C. FOR 1 MINUTE TO 5 HOURS AN INTIMATE MIXTURE OF FROM 30 TO 70 MOLE PERCENT FE2O3, 0.2 TO 50 MOLE PERCENT BEO, AND THE REMAINDER COMPRISING AT LEAST 20 MOLE PERCENT ONE OTHER OXIDE FROM THE CLASS CONSISTING OF THE OXIDES OF MANGANESE, ZINC, MAGNESIUM, NICKEL, CADMIUM AND COPPER. 